[HELP]Failed to execute pipeline.

[Milkwayboat <mi...@hotmail.com>]

The error stack I got:       
Failed to execute pipeline. 

org.apache.cocoon.ProcessingException: Failed to execute pipeline.: java.lang.NullPointerException

Original Exception: java.lang.NullPointerException         at org.apache.xml.serializer.ToStream.ensurePrefixIsDeclared(ToStream.java:2675)          at org.apache.xml.serializer.ToStream.startElement(ToStream.java:1777)          at org.apache.xalan.transformer.TransformerIdentityImpl.startElement(TransformerIdentityImpl.java:1073)          at org.apache.cocoon.xml.AbstractXMLPipe.startElement(AbstractXMLPipe.java:130)          at org.apache.cocoon.xml.AbstractXMLPipe.startElement(AbstractXMLPipe.java:130)          at org.apache.cocoon.transformation.AbstractSAXTransformer.startTransformingElement(AbstractSAXTransformer.java:692)          at org.apache.cocoon.transformation.SQLTransformer.start(SQLTransformer.java:801)          at org.apache.cocoon.transformation.SQLTransformer.executeQuery(SQLTransformer.java:340)          at org.apache.cocoon.transformation.SQLTransformer.endExecuteQueryElement(SQLTransformer.java:493)          at org.apache.cocoon.transformation.SQLTransformer.endTransformingElement(SQLTransformer.java:774)          at org.apache.cocoon.transformation.AbstractSAXTransformer.endElement(AbstractSAXTransformer.java:358) What I did:
     
1. I copied the "mysql-connector-java-3.0.11-stable-bin.jar" to $COCOON_HOME/WEB-INF/lib 
2. add the following to the web.xml
   <!-- For MySQL Driver: -->
        com.mysql.jdbc.Driver
3. add the following to the cocoon.xconf
  <jdbc name="YourPoolName">
    <pool-controller min="5" max="10"/>
    <dburl>jdbc:mysql://boss.mylab.org:3306/tbdb?autoReconnect=true</dburl>
    <user>YourUsername</user>
    <password>YourPassword</password>
  </jdbc>

  in fact I am not quite sure the port number, database name, user name and password above.
   A>  the database server doesn't require an user name or password to use the database, but it dos require an account to login in to the OS, I don't know  how to set the user and password to the OS ?
   B> also, I don't know if the port number is right? Is it just a random un-used one, or there is a specific port number for mysql in unix?
   C> I am not sure the database name too. After I login on to the server by ssh, I can type
              mysql
              use tbdb
and then, I can inquery the table I want, 
so is "tbdb"  the one I should set after the port number?

4: here is what I add to the sitemap.xmap
   <map:match pattern="allUsers">
      <map:generate src="allUsers.xml" /> 
      <map:transform type="sql">
        <map:parameter name="use-connection" value="YourPoolName" /> 
        <map:parameter name="show-nr-of-rows" value="true" /> 
        <map:parameter name="clob-encoding" value="UTF-8" /> 
  </map:transform>
    <map:serialize type="xml" /> 
  </map:match>
5, here is the allUsers.xml
  <?xml version="1.0" ?> 
  <document>
   <execute-query xmlns="http://apache.org/cocoon/SQL/2.0">
 <query name="allUsers">
  select uid from users; 
  </query>
  </execute-query>
  </document>

So I started the server and input the Url, the response is very very slow(about 5 minutes) and what I got the above error stack.
Now I totally have no idea why

Thanks for your help and time!